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[email protected] phil-news-nospam@ipal.net is offline
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Default Surge / Ground / Lightning

In alt.engineering.electrical Eric wrote:

| I can attest to vhf/uhf content in lightning strikes. I worked for a
| communications outfit. We owned and maintained a number of comm sites
| with towers and antennas. One strike on an antenna destroyed the LDF rf
| cable all the way to the polyphaser at the bottom of the tower. It had
| blowouts at about 1 foot intervals all down it's length suggesting a
| 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
| energy at that frequency..

Apparently you had some kind of resonance involved. Maybe the antenna itself
can cause that. Or the output tank circuit in the transmitter. Once you have
the resonance to narrowband the energy, it would only take a reflection back
up the line and you turn a propogating surge into standing waves.

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